## Jeffrey O. Shallit

#### ProfessorSchool of Computer ScienceUniversity of WaterlooWaterloo, Ontario N2L 3G1 Canada Office: Davis Centre 3134 Telephone: (519) 888-4567 x 34804 Fax: (519) 885-1208 E-mail: shallit at uwaterloo . ca GPS: 43.4727 °, -80.5424 °

Areas of interest:
Combinatorics on words, formal languages and automata theory (especially connections with number theory), algorithmic number theory (primality testing, factoring, etc.), history of mathematics and computer science, ethical use of computers, debunking pseudoscience and pseudomathematics.

Foreign member, Finnish Academy of Science and Letters. Elected 2020.

Here is an interview with me and Toufik Mansour, describing some of my favorite open problems.

Here I am on google scholar citations.

There is a constant 1.369451... named after me. It is not as important as Euler's constant. Here is a Maple file to compute some estimates of it. Recently Sadov computed many more digits; his paper appeared in Mathematical Notes 110 (2021), 375-392.

There are two different sequences named after me. The first appeared in D. Boyd, Linear recurrence relations for some generalized Pisot sequences, Advances in Number Theory, Oxford University Press, 1993, pp. 333-340, and is defined as follows: a0 = 8, a1 = 55, and for n ≥ 1 we have an+1 is the least integer such that an+1/an > an/an–1. The sequence starts 8, 55, 379, 2612, 18002, ... and appears to satisfy the recurrence an = 6an–1 + 7an–2 – 5an–3 – 6an–4. But it does not; the identity fails at n = 11056. See here for more details.

The second is actually a family of sequences, defined here by Moree et al.

## Unprofessional Activities

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